NA CX-5 with Cylinder Deactivation Engine Repairs - Report In

[Jack Rabbit]

Fair, but I'm still pretty sure that there is no ruleset for when a manufacturer issues a TSB or SA. It's up to their discretion. While a TSB or SA is more likely to be issued for a more common problem, they are not only issued for common problems, as you assert.




It would have been faster and easier for you to just do the research..

Maybe but I already read the posts and know there is a problem with the CD and my posts mentioned the CDs have head problems.

I shouldn't have to take time to search and repost other threads and stuff just to prove a position to other members.

But so be it.

 

[sm1ke]

Maybe but I already read the posts and know there is a problem with the CD and my posts mentioned the CDs have head problems.

I shouldn't have to take time to search and repost other threads and stuff just to prove a position to other members.

But so be it.

Yes, but "CDs have head problems" is not being disputed. Just saying CDs have head problems is too vague. Reports of problems with solutions/repairs and mileage on the vehicle were requested, likely to get a slightly better idea of how widespread these problems are.

 

[181962]

I shouldn't have to take time to search and repost other threads and stuff just to prove a position to other members.

True, you don't have to do anything. But aren't we all decades-weary of people asserting things on social media without references or backup?

 

[181962]

Turbo CX-5 came out b4 Nov 2019. Bought our turbo in Aug 2019. They were out either spring or early summer 2019.

Actually I think it was closer to Nov 2018. I typed the wrong year. That makes it even harder to tell what a poster is complaining about if they don't specify the trim or engine.

 

[181962]

So, how many actual reports of engine problems on the NA CX-5 with CD across all of the platforms discussed so far? Just so we have a running tally.

I've applied my godlike omniscience to all sources and found there have been 1,506 engine failures for just 2018 CD engines in the US representing exactly 1% of unit sales.

 

[yrwei52]

And a new case of cracked cylinder head on the 2.5L NA with CD here:

Cracked Cylinder Head with Oil leaking...How common is this?

 

[yrwei52]

I counted 4, two CX-5 and two Mazda 3, though not all are confirmed cracked cylinder heads,
⋯
So, yes, there are instances to be sure.

I counted 5 and you counted 4 in this thread?
Cracked Cylinder Head with Oil leaking...How common is this??

1. Post #8 by hw4ng3r
2018 CX-5 GT had a cracked cylinder head at 22K miles.

2. Post #16 by casey123e
2018 CX-5 had a cracked cylinder head at 25k miles.

3. Post #39 by Mazdad93
2019 Mazda 3 with CD had cracked cylinder head.

4. Post #41 by sfbenfica
2020 Mazda3 2.5L AWD with CD had oil leak and cracked cylinder head.

5. Post #98 by mkristo2
2019 CX-5 2.5L had cracked cylinder head at 30K miles.

And there’s a new post with oil leak and definitely caused by cracked head:

Post #118 by nolig36
2018 Mazda6 2.5L NA with CD.

This one is a 2.5T:

Post #103 by ddingle
2020 CX-5 GT-R had cracked cylinder head at 40K miles.

Post #104 by walt had a YT link for a 2020 Mazda3 2.5L with CD which has oil leak and a cracked head at 47K miles. But the poster sfbenfica2000 should have posted the same case here.

The more interesting posts are by thispart starting from post #26. He is a service tech at a Mazda dealership. He claimed he was working on a head replacement for a CX-5 at the time after a 2-month wait on parts. His dealership had replaced 9 ~ 10 heads last year (2021) but didn’t clarify how many among them are for the 2.5L with CD.

 

[MyFirstMazda]

If I have an engine problem I will certainly post it here. I have a 2018 first year model with CD. I have low mileage though.

 

[181962]

If I have an engine problem I will certainly post it here. I have a 2018 first year model with CD. I have low mileage though.

All evidence to date indicates the odds are heavily in your favor. In 2018 alone, 150,000 CX-5s were sold in the US, all 2.5L NA with CD. Globally, hundreds of thousands more of these engines have been sold across models. Actually 100,000's more in the US for CX-5 alone.

And yet posters such as @yrwei52 bend over backward to claim this engine is fatally flawed based on a theory, not data. There are 3 cases for 2018 noted in post #47 out of those 150,000 units. Check some other forum sites and you'll find a few more. A few more here and there for models other than CX-5. However, as I facetiously indicated above, you'd need to identify 1,500 failures in the US 2018's just to get to a 1% failure rate. How many failures are there out in the wild? Nobody but Mazda could tell you for sure.

However, Consumer Reports continues to give good reliability ratings in the engine-major category for CX-5 for all years from 2018 onward. 2018 and 2019 get a 4 out of 5 rating which is in fact the same as 2017 pre-CD. 2020, 2021 and 2022 are rated 5 out of 5. 2019 forward includes a mix of turbo models which appear to be more problematic.

For perspective, Consumer Reports receives about 300,000 survey responses per year from actual US auto owners. Mazda has had about a 2% average US market share over recent years. This suggests Consumer Reports receives something in the vicinity of 6,000 responses per year from Mazda owners, a high percentage of which would be CX-5 owners given US sales data in recent years. That's a statistically significant sample. And that trumps a handful of anecdotes across a handful of web sites.

 

[181962]

The more interesting posts are by this part starting from post #26. He is a service tech at a Mazda dealership. He claimed he was working on a head replacement for a CX-5 at the time after a 2-month wait on parts. His dealership had replaced 9 ~ 10 heads last year (2021) but didn’t clarify how many among them are for the 2.5L with CD.

His responses were fuzzy and beg a few question including turbo vs. NA. I notice he's in Canada. If there is a cracked cylinder head frequency above the industry norm, which has obviously not been demonstrated, perhaps it is a cold climate phenomenon.

 

[yrwei52]

⋯
And yet posters such as @yrwei52 bend over backward to claim this engine is fatally flawed based on a theory, not data.

I dislike the cylinder deactivation is not just based on a theory, but also based on the history of CD since 1980’s when GM invented it. Since then CD is nothing but troubles whoever used it. Just Google the cylinder deactivation everybody can see. Also to implement the CD, it complicates the engine, sacrifices the durability, and the reward on gas savings is very minimum.

Now if you know Russian, you’ll understand it more from these videos which shows why the cylinder head is prone to crack on the 2.5L NA with CD:

Mazda 3 Skyactiv-G 2.5 N/A with C/D (2019 year 20.000 km.) - really interesting and detailed process of removing the head and welding the crack. He is speaking Russian but everything is clear without a verbal explanation:

Mazda 3 Skyactiv-G 2.5 Трещина в головке. Часть 1, Знакомство Oil leak from a cracked cylinder head

Всем привет, сегодня покажу проблему с которой я борюсь. Это треснутая головка блока двигателя Mazda 3 в кузове BP с мотором Skyactiv-G объёмом 2.5Это первая...

www.youtube.com

Mazda 3 Skyactiv-G 2.5 Трещина в головке. Часть 2, Сварка

Всем привет, сегодня покажу проблему с которой я борюсь. Это треснутая головка блока двигателя Mazda 3 в кузове BP с мотором Skyactiv-G объёмом 2.5Это вторая...

www.youtube.com

Mazda 3 Skyactiv-G 2.5 Трещина в головке. Часть 3, БОЛЬ

Всем привет, сегодня покажу проблему с которой я борюсь. Это треснутая головка блока двигателя Mazda 3 в кузове BP с мотором Skyactiv-G объёмом 2.5Это третья...

www.youtube.com

Here’s a proof. The thickness of aluminum in the problem area is only 2mm thick with aluminum material? No wonder that weak area is prone to crack.

Regarding the topic,
The mechanic from the videos I posted before seems to be very experienced and he was literally shocked when he started welding the crack. The thickness of aluminum in that area was around 2mm. As an example, he was comparing and showing some Chinese brand cylinder head he found in his workshop, and the thickness of the aluminum edge there was about 7mm, which is approx 3,5 thicker.
Finally, he was highly disappointed with the way how Mazda designed the new cylinder head, specifically in saving the cost of aluminum in that area.
His advice was to not leave this particular engine downtime for a long period, as hydraulic cranks (the area where cracks appear)can possibly get jammed and cause significant stress when the engine is starting again after a long downtime.

 

[181962]

I dislike the cylinder deactivation is not just based on a theory, but also based on the history of CD since 1980’s when GM invented it.

Here’s a proof. The thickness of aluminum in the problem area is only 2mm thick with aluminum material? No wonder that weak area is prone to crack.

Those are theories not supported by data.

 

[yrwei52]

Those are theories not supported by data.

So all the documented problems started from GM, and many class-action lawsuits against cylinder deactivation engines are not historical dara? Have you watched the Youtube video that actually show the removed cylinder head with crack and he patches the crack up?

 

[Sig cx-5]

So all the documented problems started from GM, and many class-action lawsuits against cylinder deactivation engines are not historical dara? Have you watched the Youtube video that actually show the removed cylinder head with crack and he patches the crack up?

I thought this discussion was about the current CD being used in Mazda's, not what GM was using back in the early 2000's.

As has been said, Mazda is one of the most reliable brands out there. If CD was as big an issue as some seem to believe, that wouldn't be the case.

 

[181962]

So all the documented problems started from GM, and many class-action lawsuits against cylinder deactivation engines are not historical data?

Am I on a GM forum? Projecting from one car maker to another across decades amounts to a theory.

The Chevy Vega was one of the earliest, if not the earliest, mass produced vehicle with an aluminum block. That model had a high incidence of early block failures. Should we not buy cars with aluminum blocks? Good luck finding one.

Have you watched the Youtube video that actually show the removed cylinder head with crack and he patches the crack up?

No, because there's little point in it. To repeat, why should I care about one anecdote or even a handful compared against 100,000's on the road? I don't know how many times it can be repeated, but it's a matter of percentages. I would expect some percentage failures with any engine regardless of its characteristics or who made it, cracked cylinder heads or otherwise. It's a matter of how high that percentage gets.

Your theory may prove correct over the long haul but to date it remains just a theory. It also depends on what you consider a long haul.

 

[yrwei52]

Am I on a GM forum? Projecting from one car maker to another across decades amounts to a theory.

Not just the GM, Honda、Ford、Chrysler those who have used cylinder deactivation on their V8 or V6 all have their share of problems, even the class action lawsuit. They all have to tune down the frequency of cylinder deactivation cycle, or alternating cylinders for deactivation. The CD idea is flawed, a bad concept which can’t be overcome especially on durability no matter how hard the car manufacture tried. Mazda doesn’t immune from a bad concept.

The Chevy Vega was one of the earliest, if not the earliest, mass produced vehicle with an aluminum block. That model had a high incidence of early block failures. Should we not buy cars with aluminum blocks? Good luck finding one.

You’re trying to compare apples to oranges. Chevy Vega was using “all” aluminum cylinder block, but every modern aluminum cylinder block has metal sleeves inside for cylinder walls for longer wear. Aluminum is a soft metal, hence the cChevy Vega’s block wearer out fast although GM claimed they had used a special coating on the aluminum cylinder wall for longer wear but apparently that didn’t work.

Now we use the aluminum cylinder block for an example. Modern aluminum cylinder block uses the metal sleeves for cylinder walls for durability. It’s s major improvement and takes care of a major flaw on aluminum block. But I don’t see Mazda improved any thing on its cylinder deactivation system. The system is similar to those GM CD system back to 1980’s other than it has more complicated software controls to the components.

No, because there's little point in it. To repeat, why should I care about one anecdote or even a handful compared against 100,000's on the road? I don't know how many times it can be repeated, but it's a matter of percentages. I would expect some percentage failures with any engine regardless of its characteristics or who made it, cracked cylinder heads or otherwise. It's a matter of how high that percentage gets.

The video showed the actual weak point on the modified cylinder head used for 2.5L NA with CD. The guy is very professional and knows the engine well. Yet you refused to watch it and see why there’re cases of cracked cylinder head? The proof is right in the video showing the cylinder head is flawed due to the modification to accommodate the CD system. The failure rate may be low right now, but once it fails, it’s going to cost the car owner an arm and a leg if there’s no warranty. Every CX-5 owner having this engine should be concerned.

Your theory may prove correct over the long haul but to date it remains just a theory. It also depends on what you consider a long haul.

Again, I’m saying this not just based on a theory, but is based on the historical data as Mazda didn’t change much on its cylinder deactivation system, and the evidence of flawed cylinder head design as Mazda make the area too thin while others are 2X thicker. And remember there’s another ticking time bomb on hydraulic lift adjusters where we’ve started to see some reports coming out with higher mileages. This’s another pretty expensive repair if there’s no warranty to cover it.

 

[MyFirstMazda]

Only time will tell. And it is true that the more complex something is made, there is more that can go wrong. Thus far I think my engine is reliable, but if it does crap out I would denounce CD like yrwei52 does. I denounce turbos because I had one that went bad, and I think all of them will fail. I will never get a car with a turbocharger.

 

[yrwei52]

⋯ And remember there’s another ticking time bomb on hydraulic lift adjusters where we’ve started to see some reports coming out with higher mileages. This’s another pretty expensive repair if there’s no warranty to cover it.

Here is another recent example of hydraulic lift adjuster problem on a 2.5L NA with CD just happens to be mentioned:

2018 mazda cx5. 112000 miles
⋯
last month I had the adjustable Hydraulic lifters replaced due to lifter ticking noise. This was related to mazda's TSB regarding issues with their cylinder deactivation tech. That issue waa resolved.

I'm not sure if the valve lifters had anything to do with what I'm experiencing now. Thoughts?

 

[yrwei52]

Only time will tell. And it is true that the more complex something is made, there is more that can go wrong. Thus far I think my engine is reliable, but if it does crap out I would denounce CD like yrwei52 does. I denounce turbos because I had one that went bad, and I think all of them will fail. I will never get a car with a turbocharger.

Mazda’s cylinder deactivation doesn’t offer anything new other than advertised as the first CD 4-cylinder engine available in North America. Based on history I can already predict it’s going to have durability issue like every other CD engines.

I’m personally also trying to avoid any turbo engines, although I believe the reliability issue has been improved greatly. The theory itself is sound, the only problem is the durability caused by the high heat.

On the other hand, cylinder deactivation based on the variable displacement concept simply can’t be implemented easily to the current ICE. Too many unnecessary passive moving parts when the CD is activated, which is dragging down the efficiency. The uneven and changing heat generated by the process also becomes a major factor to wear out the engine much faster.

 

[madar]

Mazda’s cylinder deactivation doesn’t offer anything new other than advertised as the first CD 4-cylinder engine available in North America. Based on history I can already predict it’s going to have durability issue like every other CD engines.

I’m personally also trying to avoid any turbo engines, although I believe the reliability issue has been improved greatly. The theory itself is sound, the only problem is the durability caused by the high heat.

On the other hand, cylinder deactivation based on the variable displacement concept simply can’t be implemented easily to the current ICE. Too many unnecessary passive moving parts when the CD is activated, which is dragging down the efficiency. The uneven and changing heat generated by the process also becomes a major factor to wear out the engine much faster.

I share your sentiment exactly. When Mazda introduced CD, it was a big WTH-are-they-trying-to-do moment. IMO, the pre 2018 2.5 liter was just about bullet proof, virtually no real problems reported over the years except an oil leak here and there.

All the talk about the Vega brings back memories. If memory serves, I believe coolant would seep into the cylinder and attack the special coating. Later on they introduced iron sleeves and it was a much improved engine.

The Cadillac 4-6-8 CD engine was just a nightmare.